there were less than 5 girls on my computer science class, so unless woman are claim that they should have the job without education. I can totally see the reason why there is a gender diversity in IT?
Secondly, if you hear "startup" and think "developers" then you're ignoring at least 50% of the work necessary to make the business a success, all of which can (and often should) be done by someone without a CS degree. There's a lot more to tech than writing code.
Their tl;dr answer is that video games happened, and they were marketed exclusively to boys; that's what created and drove the cultural rift.